If the blades are the same I take a couple pieces of all thread and bolt the blades together through the tangs into a big brick. I then use Zip ties on the ends of the all thread to strap that brick down to a sheet of micarta (holes drilled in it). A length of bent cardboard across the tips for good measure and wrap it up, stuff it into a USPS Regional Rate A box (size 11"X13") with padding in the empty spaces and can ship ~40 knives for ~$6 via priority mail, which is pretty fast. I've shipped this way many times and never had any problem. The knives are tied down so they can't damage the box, the postman, or each other.